Secondary batteries are widely used as a power source of a portable electronic device such as a notebook computer and a cellular phone and also used as a power source of an electric vehicle. Various proposals have been made for reducing degradation of battery performance associated with a temperature change (for example, see Patent Documents 1 and 2).
In a secondary battery electrode described in Patent Document 1, a plurality of minute cells are formed as electrode layers on a collector serving as a substrate in order to relieve thermal stress produced from a temperature change within the secondary battery.
In the secondary battery electrode described in Patent Document 1, the plurality of minute cells formed on the collector include different amounts of conductive agent to provide uniform temperature distribution on the secondary battery electrode. Specifically, a minute cell located at the center of the collector contains the smallest amount of conductive agent, while a minute cell located at the end of the collector contains the largest amount of conductive agent.
[Patent Document 1] Japanese Patent Laid-Open No. 2005-11660 (FIGS. 1, 2, 11 and the like)
[Patent Document 2] Japanese Patent Laid-Open No. 2004-178914